1. Field of the Invention
This invention relates to lubricants containing an antimicrobial compound.
2. Brief Description of the Prior Art
Lubricants containing an antimicrobial compound have been generally known. Commonly, such lubricants include an antimicrobial compound for one or more of a number of reasons, including preservation of the lubricant from deterioration or contamination, and protection of those coming in contact with the lubricant from a condition known as contact dermatitis. For these and similar reasons for the use of an antimicrobial compound, the antimicrobial compound must be active in the presence of the lubricant's substituents and strong enough to perform the function for which it is used. In the typical instances of preserving the lubricant or preventing contact dermatitis, the antimicrobial compounds heretofore proposed for use have been toxic to humans if ingested. Consequently, antimicrobial compound-containing lubricants have been limited to certain applications in which human ingestion is unlikely because they are too aggressive for human ingestion.
Moreover, certain applications for lubricants require the use of a special class of lubricants called boundary lubricants. Such applications often pose severe loading, high speed, or high temperature conditions that non-boundary lubricants cannot adequately tolerate. Consequently, extreme pressure additives have been developed that, when added to a base lubricant, produce a boundary lubricant for these severe applications. The presence of extreme pressure additives in lubricants is very important if a lubricant is to perform favorably under heavily loaded, high speed, or high temperature conditions. Typical of such an application are dental tools such as dental hand pieces, and some medical devices, where boundary lubrication is essential in cage/ball and cage/race bearing contacts. In the absence of a suitable boundary lubricant, such devices wear out much too soon because metal to metal contact creates unacceptable wear and surface distress.
Dental tools and some medical devices, in which use of a boundary lubricant would be highly desirable, come into contact with internal parts of the human body; dental tools with the oral cavity, of course. However, extreme pressure additives used in boundary lubricants are so highly toxic that they are unsuitable for use in devices that may come into contact with internal parts of the human body, such as the oral cavity in the case of dental tools. Furthermore, known antimicrobial compounds used in lubricants are also too aggressive for such uses.